Saw grinder



C. E. DRAKE SAW GRINDER July 6, 1954 5 Sheets-Sheet l Filed Jan. 3l,1951 INVENToR E, BRAKE f W W CLAUD c. E. BRAKE 2,682,790

SAW GRINDER July 6, 1954 Filed Jan. 3l, 1951 5 Sheets-Sheet 2 FIG. 8.

INVENToR. CLAUD E. DRAKE FIG. 6.

July 6, 1954 c. E. DRAKE 2,682,79Q

lSAW GRINDER Filed Jan- 5l, 1951 5 Sheets-Sheet 5 FIG. 4.

' FIG. 3

INVENToR. (1L-Aun E. DRAKE July 6, 1954 vQ E BRAKE 2,682,790

SAW GRINDER Filed Jann. 5l, 1951 5 Sheets-Sheet 4 A y 50 \f f 77 /f/fNVENTOR.

CFJLAuo E. BRAKE C. E. DRAKE Jlly 6, 1954 SAW GRINDER 5 Sheets-Sheet 5Filed Jan. 31, 1951 INVENTOR. CLAUD E. D RAKE Patented July 6, 14954UNITED STATES PATENT 'OFFICE SAW GRINDER Claud E. Drake, Brentwood, Mo.

Application January 31, 1951, Serial No. 208,814

(Cl. '7G-40) 9 Claims. 1

This invention relates in general to certain new and useful improvementsin saw grinders and, more particularly, toa grinder for grinding andsharpening circular cutters for dense alloy tips.

One of the principal problems in the manufacture and sharpening ofcircular cutters having dense alloy tips is to grind the tips in asimple and eicient manner without generating excessive heat which willreduce the efficiency and life of the tip. Such grinding operationsfurthermore involve a rather large number of variables inasmuch as thereare many gauges and sizes of saws with a wide Variety of tooth shapesand pitches. In order to grind such saws mechanically, therefore, it isnecessary to provide a grinding machine which can be quickly andconveniently set up to accommodate any of these different variables andwill not require the expenditure of an unprotably large amount of set-uptime on the part of the operator.

It is, therefore, the primary object of the present invention to providea saw grinding machine which is relatively simple and inexpensive inconstruction and maintenance and is capable of performing highlyaccurate and precise operations on the teeth of carbide tipped circularcutters.

It is another object of the present invention to provide a saw grinderof the type stated which is readily adaptable and adjustable for theaccommodation of a wide range of different shapes, sizes, andconfigurations in the saws to be ground and can be quickly andeconomically set up to accommodate any particular set of dimensions orconditions.

With the above and other objects in view, my invention resides in thenovel features of form, construction, arrangement, and combination ofparts presently described and pointed out in the claims.

In the accompanying drawings sheets)- Figure 1 is a front elevationalviewof a saw grinder constructed in accordance with and embodying thepresent invention;

Figure 2 is a top plan view of the saw grinder;

Figures 3 and 4 are opposite end elevational views of the saw grindertaken, respectively, from the right-hand and left-hand ends thereof(reference being made to Figure 1) Figures 5 and 6 are fragmentarysectional views taken along lines 5 5 and 6 6, respectively, of Figurel;

Figure 7 is a fragmentary sectional view taken along line 'I I of Figure6;

Figures 8 and 9 are fragmentary sectional views taken along lines 8 8and 9 9, respectively, of Figure 2;

Figure Vl() is a fragmentary sectional View taken i along line IiI I 0of Figure 9;

Figure 11 is a fragmentary sectional View taken along line l I I I ofFigure 1;

Figure`12 is a fragmentary sectional view taken along line I2 I 2 ofFigure 2;

Figures 13, 14, 15 and 16 are fragmentary views taken along lines I3 I3,I4 Ili, I5-I5, and IS-l 6, respectively, of Figure l2 v Figure 17 is afragmentary front elevational View of the vertical adjustment slide witha setting gauge removably mounted thereon; and

Figures 18, 19, and 20 are fragmentary sectional views taken along linesI 3 i8, I9-I9, and 2 2, respectively, of Figure 17.

Referring now in more detail and by reference characters to thedrawings, which illustrate a preferred embodiment of the presentinvention, A designates agrinder comprising a relatively heavy flathorizontal base plate I and four upstanding plate-like wall memberswelded together along their vertical margins to form an open toprectilinear machine frame including a front wall 2, a rear wall .3, andside walls 4, 5. Midway between the side walls 4, 5, and extendingtransversely between the front and rear walls 2, 3, is an intermediatevertical reinforcement wall 6. Similarly, welded between thereinforcement wall 6 and the side wall 4 in downwardly disposed relationto the upward margins thereof is a horizontal supporting plate l. Also`welded to the upper margins of the front wall 2, rear wall 3, and sideWall 5 and extending horizontally inwardly thereacross for a shortdistance from the side wall 5 is a top plate 8.

Welded upon the upper face of the top plate 8 is a pair of transverselyaligned upstanding ears IIJ, II, and journaled horizontally therein is ashort shaft I2 which projects horizontally forwardly beyond the frontplate 2 for supporting engagement with the upper end of a swingablemounting element or plate I3, which, in turn, extends angularlydownwardly across the front face of the front wall 2 and is integrallyprovided with a vertically upwardly extending arm I4, a rearwardlyfitting horizontal arm I5, and a downwardly extending arcuate arm I6,the latter having its rearward margins I1 machined off to a radius orarc, the center of which is coincident with the center line of the shaftI2. .The plate I3 is rmly held in any adjusted position of arcuatemovement about the center lineV of the shaft I2, within the overalllimits of its swing, by a clamp I8 mounted around and engaging itsrearward portion in the area adjacent the arcuate margin I'I, the clampbeing arranged from a manual manipulation by the screw wheel I9. Theplate I3 is further clamped into position by the long clamping bar 2U,which is similarly held in place by clamping screws 2|, having handwheels 22, for facilitating the manual manipulation thereof.

Welded upon the outer face of the side wall ll is a short bracket arm 23which is provided with a horizontal swivel pin 24 carried in a splitjournal it and integrally joined at its forwardly presenting' ends witha more or less vertically disposed rocking sleeve 2t which is internallybored for operatively receiving a shaft 21, which is rotatably butnon-shiftably mounted therein.

t its upward extended end the shaft 21 is pro vided with a hand wheel 28and at its lower end is threaded for operative engagement within aninternally threaded collar 29, which is, in turn, integrally providedwith a forwardly extending swivel pin 36, roclably mounted in a splitjournal 3|, secured upon a short bracket arm 32, rigidly mounted uponthe rear face of the plate arm l5. By appropriate rotation of the handwheel 28 the shaft 21 will be turned and the entire varm swung upwardlyor downwardly into any desired position of adjustment. In thisconnection it will be noted that the free or downwardly depending end ofthe shaft 21 will swing through a short arc toward and away from theside wall i to accommodate for the relative in-and-out movement of thebracket 32 due to the arcuate path through which it moves around thecenter line of the shaft l2.

Welded or otherwise rigidly secured upon the forwardly presented face ofthe plate I3 is an outwardly extending bracket 33 having a substantiallyhorizontal split sleeve Sil, clamped in and extending horizontallythrough the split sleeve .til is a relatively large solid steel shaft 35and slidably mounted thereon, in straddling position to the sleeve 34 isan upwardly extending rocking frame t6 which is adapted both fortoand-fro rocking movement about the longitudinal axis or center line ofthe shaft 35 and transversely sliding movement along the shaft 35. Therocking frame 36 projects upwardly and forwardly in an arcuate sweep andis provided at its upward end with a tubular bearing 31. Mounted in andextending through the bearing 31 is a shaft 3B removably provided at itsouter end with a conventional diamond wheel 39 and at its opposite endextending rearwardly through a tail bearing Lit carried by a supportingarm All. At such rearward end the shaft 3S is provided with a smallpulley 42 which is operatively connected by a conventional driving beltit to a driving pulley d4 pinned upon the shaft of a driving motor Mlocated upon and carried by the arm 4I.

Bolted rigidly to the rearward end of the rocking frame 36 is a tubularsleeve 35 which is disposed concentrically around and slidably upon therearwardly projecting end of the shaft Rotatably but non-slidablymounted externally upon the sleeve 36 is a collar 45. Welded orotherwise rigidly connected upon the peripheral face of the collar l5 isa triangular gusset plate 45 and integrally joined to a nut-formingelement 46 which is threadedly mounted on a lead screw @l1 journalednon-shiftably at its opposite ends in bearings d8, 49, which are, inturn, rigidly secured on the forwardly presented face of the plate arml5. The lead screw 41 is rigidly connected at its one end with anaxially extending shaft 5@ journaled in an auxiliary bearing 5l' andprovided at its end with a bevel gear 52 which meshes with a secondbevel gear 53 pinned to the lower end of an upwardly extendingintermediate shaft 54, the latter being journaled at its upward end in aforwardly extending support plate 55 and provided with a bevel gear 5t,which, in turn, meshes with a bevel gear 51 pinned upon the rearward endof a shaft 5S. The shaft 53 is journaled at its ends respectively in theupper end of the plate arm ld and a short supportingplate 59 welded uponand extending upwardly from the plate E5. At its forward or projectingend the shaft 58 is provided with a hand wheel 6i) to facilitatemanipulation thereof. It will be seen by reference to Figures 2 and 4that the shaft 58 may be suitably turned by manipulation of the handwheel S9, whereupon the rotative movement thereof will be transmit tedthrough the bevel gears 52, 53, 56, 51, to the lead screw fil. As willbe seen by reference to Figures 1 and 2, rotation of the lead screw 531will drive the nut-forming element 46 forwardly or rearwardly and thismotion will be transmitted through the gusset plate 5 and collar L15 tothe arm di so that the arm il and all other structure carried therebywill be bodily moved forwardly or rearwardly respectively to rotation ofthe hand wheel Bil and the grinding wheel 39 will thereby be fed acrossthe work.

Bolted upon the plate 1 is a motor Si which is connected through aconventional speed reducer 32 to a driving pulley $3 which is, in turn,connected by means of a belt @il to a pulley t5 pinned upon ahorizontally journaled shaft 5t. Locked to one free end of the shaft @dis a driving plate t1 provided with a radially extending slide-- formingslot t8 for shiftably receiving a slide block 69, having an internallocking slot lil for co-operation with locking bolts 1i by which it maybe held in any position of radial adjustment across the face of theplate 61. Formed integrally with and extending laterally outwardly fromthe slide blocks E is a stud 12 provided at its outer end with theball-and-socket fitting 13 which is internally bored and threaded forreceiving one threaded end of a turn-bucl le rod 14. The other threadedend of the turn-buckle rod is similarly threaded into a secondball-andsoclret fitting 15 which is, in turn, swivelly mounted upon astud 16 rigidly secured to a bracket plate 11 which is, in turn,securely bolted upon the inner face of the arm el. When the motor 5! isenergized the shaft 65 will be rotated and the stud 1i) will function asan eccentric crank pin to shift the turn-buclrle rod 14 forwardly andbackwardly and thereby rocking the arm t! together with the motor liti',shaft Sil, and grinding wheel 39, backwardly and forwardly through alimited are, The amount of arcuate movement thus imparted to thegrinding wheel will depend upon the degree of throw of the crank pin orstud 12 and this, in turn, depends upon the relative position of radialadjustment thereof with respect to the driving plate G1. Inasmuch as thecollar d5 is rotatably but nonshiftably mounted on the sleeve 36 thefeeding movement of the rocking arm 4| and the grinding wheel 39,operatively supported thereby, will not interfere with the toeand-frorocking movement imparted thereto, but the motor El and conversely therocking movement which is transmitted by the motor GI through theturn-buckle rod 1li will not impede the feeding movement just mentionedsince the turn-buckle rod 14 is connected at both ends by means of theball-andsocket joints 13, 15. It should be noted in this connection thatthe axis of the shaft along which the feeding movement of the rockingarm 4| takes place always lies in a vertical plane which is parallel tothe shaft 66, hence, the distance between the outer and inner limits ofmovement of the stud- 16 and 12respectively, may 'vary somewhat. Thisvariation can be compensated by adjustment of the turn-buckle screw14.which may be turned by appropriate manipulation of the hand wheel 18.

Rigidly secured to and extending outwardly from the side wall 5 adjacentthe upper margin thereof is a pair of spaced horizontal bars 19, crossconnected at their outer ends by an end plate 80 and rigidly supportedby angularly extending beams which are, in turn, welded or` otherwisesecured at their lower ends tothe base plate I. Adjustably mounted uponthe 4bars 19 is a pair of axially aligned journals S2 for rockablysupporting a horizontal shaft 83 which extends therethrough and at itsforward projecting end is rigidly provided with a frame-forming element84, the latter being integrally provided with forwardly projecting faceparallel ears 85 for rockably supporting a horizontally disposed tubularshaft 86 which projects rearwardly and is provided with a verticallydisposed depending slide 31 carrying a conventional lead screw 83 and aslide block $9, which can be vertically adjusted by appropriate rotationof the lead screw 88. The slide block 89 projects laterally from theslide 81 and is provided with a work-supporting arbor 90 having athreaded end for receiving a mounting nut 9| by which it is rigidlysecured to the slide 81. 81, the arbor 90 is integrally provided with adiametrally enlarged hub 92 upon which is mounted a backing collar 93which may be optionally locked in place by means of a set screw zr.Outwardly of the hub 92 the arbor 90 is again diametrally reduced toprovide a shaft-like portion 92 the outer end of which is threaded toreceive a clamping nut 93 which impinges upon its inner face against aspring 915 disposed encirclingly about the arbor section 92 and abuts atits inner end against a conventional ball bearing thrust collar 94which, in turn, bears against the internal face of .a work centeringcone 95 adapted to accommodate the various different diameters of sawholes h which are conventionally encountered in different types ofcircular saws S.

As will be seen by reference to Figure 11 the particularly saw S, beinggrounded, may be placed upon the arbor and the work`clamping nut 93primarily tightened so that .the saw will be held more or less firmlybetween the collar 93 and the cone 95 by the tension in the spring 94.Thereupon the collar 93 may be turned inwardly or outwardly ascircumstances may require so that the midpoint ofthe tooth tip, that isto say the point along its cutting edge midway between its lateralsides, will be positioned accurately along the horizontal projection ofthe center line of the tubular shaft 86. Thereupon the set screw :l: maybe tightened and the clamping nut 93 canbe turned down so as to bringadditional tension of the spring 94 to bear upon the cone 95 assuring afirm and accurate engagement of the saw S. During the course of grindingopera- Ltions, however, when it is necessary to rotate the saw plateabout the axis of the work sup- 4porting arbor 90 in progressingsuccessive teeth into position for grinding the cone 95 will rotate withthe work due to the action of the thrust bearing 94 but the backingcollar 93 will remain stationary in itsradjusted position since it islocked in such position by the set screw rc.

Mounted on the shaft 86 is a tubular sleeve 96 secured thereto by meansof set screws 91 and integrally provided with a rearwardly extendingboss 98 to which is bolted depending reinforcement bars 99, 99',cross-connected by an L- shaped bracket |00, having a lateral leg |0|which is disposed in spaced parallel relation to the lower arcuateportion of an adjustment segment |02 rigidly secured to the outer leg 85of the frame 84. The segment |02 is provided with an arcuate slot |03,the center of which is coincident with the center line of the shaft 03and is adapted to receive a threaded stud |04 which extends therethroughand is threadedly mounted in the leg I0 I. At its outer end the stud isintegrally provided with a hand wheel |05 and a clamping washer |06.Thus by loosening the threaded stud |015l the entire arbor-carryingstructure can be swung inwardly and outwardly about the center line ofthe shaft 86 so as to place the saw plate S in various angularly dis-Forwardly of the slide posed planes with reference to the vertical faceof the front wall 2 to facilitate cutting beveled faces upon the top o-fthe saw teeth, as will presently be more fully described.

Rigidly mounted upon one end of the shaft 86 is a short transversebracket |01 having two spaced parallel ears |08 projecting forwardlytherefrom and carrying a horizontally shaft |09 upon which is rockablymounted a pair of spaced parallel depending arms H0. One of the arms l0,however, is provided with a laterally projecting stud which rockablysupports the upper end of a toggle link ||2 having a depending rod H3slidably disposed through a lateral ear H4 mounted rigidly upon thebracket element |01 and biased upwardly by an encircling spring i l5.

At their lower ends the arms ||0 carry a horizontalrod ||6 provided onits outer end with a linger-block I l1.y Rockably mounted upon a pin ||8carried by the block ||1 is a tooth-positioning finger ||9 biased forlatch-like engagement with the gullet faces of the saw teeth by means ofa spring |29. By reason of the fact that various saws have variousthicknesses it is desirable to provide for an amount of inward andoutward adjustment of the nger H9. Therefore, the rod ||6 is providedwith a threaded thumb-screw |2| which bears against the bracket |01 andserves to adjust the entire finger-supporting structure inwardly andoutwardly within desired limits.

Rigidly clamped to and extending radially from the shaft 83, along thatportion of its length located between the journals B2, is an arm |22provided at its free end with a vertically threaded f boss |23 forreceiving an adjustment screw |24 provided at its upper end with a handwheel |25 and intermediate at its ends with a locking hand wheel |26. Atits lower end the screw |24 projects through the boss |23 and bearsagainst the upper face of a cam block |21 which is integrally formedupon the outer end of an auxiliary arm |28 pivoted at its other end toan intermediate portion of the arm |22. On its under face the cam block|21 bears against a single cam |29 which is pinned upon the shaft |30.The shaft is, in turn, journaled between bearing elements |3| boltedupon the upper `face ofthe plate 8. Pinned to the shaft |30 intermediatethe bearing elements |3| is a sprocket ear |32 for operative engagementwith a sprocket chain |33, the latter being rigidly secured at one endto a tension spring |34 and at its other end to an actuating foot pedalassembly |35'. By depressing the foot pedal assembly |35 the sprocketchain |33 is drawn downwardly stretching the spring |34 and rotating thecam until the cam block |2'| drops down from the high lobe of the cam|29 thereby permitting the arm |22 to rock downwardly rocking the shaft83 and carrying the entire saw arbor supporting assembly arcuatelydownwardly about the horizontal axis of the shaft B3. This permits theentire Awork to be quickly dropped away from operative engagement withthe grinding wheel 39 after a single tooth grinding operation has beencompleted so f that the next tooth can be brought up into place bymanually rotating the saw S uponthe worksupporting arbor 90. It shouldbe noted in this connection that the clamping nut 9| will be tightenedfairly securely in place, but there will be a sufcient amount of verylimited freedom of the saw S so as to permit manual rotation from timeto time to bring various teeth into grinding position. It will also beynoted by reference to Figure 9 that the vertical grinding position ofthe tooth may be adjustedby appropriate manipulation of the screw |24after the vertical position has been preliminarily set up throughadjustment of the lead screw 88. The adjustment afforded by the screw|24 is also very convenient where a saw being ground has alternate highand low teeth. In such case,.the alternate high teeth `can besuccessively ground around the entire periphery of the saw and thereuponthe intermediate low teeth canbe ground by a second rotation of theentire periphery of the saw in successive steps and the diiference inheight of the teeth can be provided for by appropriete adjustment of thescrew 88 as gauged by the dial indicator r.

.As shown in Figures 18 to 20, inclusive, an auxiliary demountablebracket plate |36 maybe provided and may be removably held in place by athumb screw ii by which it is secured to the back face of the slide 81.The plate |33 is provided with a conventional plunger-type Verniercaliper |3'i for use in setting. up the saw plate S on the wor-l;supporting arbor with the center point of the tooth in proper grindingposition. Formed integrally with the plate and extending forwardlytherefrom is an auxiliary arm |38 provided at its outer end with aslidable plunger |39 having a downwardly presented. work-contacting foot|48. Along the portion of its length which is disposed within theinterior of the arm |38 the plunger |39 is provided with an inclinedface |4| disposed preferably at an angle of "Y to its `longitudinal axisfor motion-transferring engagement in an end of a gauge-plunger |42-extending from a conventional dial gauge |43 threadedly mounted in andcarried by thearm |38. Thus, the auxiliary plate |35 can be mounted uponthe slide 8l and the saw tip brought up. into engagement therewith.

In use the saw grinding machine A is set up by positioning the saw plateS which is to be ground upon the work-supporting arbor 9S as previouslydescribed. In making the various adjustments which lare necessaryV forsetting up the machine A the bracket plate |36` is installed as arriveat the setting for the plunger-type Vernier caliper |31. The Verniercaliper |31 is manually set to this setting and the back face of the sawplate adjusted along the work-supporting arbor Sii until it just touchesthe caliper plunger in the manner shown in Figure 20. The slide 89 isthen elevated until the upper face or cutting edge of the tip justgrazes the under face of the work-contacting foot |40 of the dial gaugeM3. This elevating action is continued until the dial gauge shows areading equivalent to the amount of material which it is desired togrind ofi" of the top face of the tooth. Thereupon the auxiliary racketplate |36, with its associated gauges, is removed and the motors 44',6|, set in operation so that the grinding wheel 39 will be rapidlyrotated and, at the same time, swung to-and-fro by the rocking movementimparted to the rocking frame 3e. When the grinding wheel 39 is up tofuli speed the hand wheel 28 is turned slowly 'traversing the arm 4|forwardly and feeding the grinding wheel across the top of the toothtip. The rapid reciprocation of the grinding wheel to-and-fro across thework makes it possible to grind with maximum eiiiciency and perfectionall types of circular saws and particularly saws which are tipped withtungsten, carbide and other dense alloy tips. The amount of materialremoved in any single pass of the wheel is so '"ht that an undue amountof heating of the tip will not take place, yet by very rapidreciprocation through a large number of passes, a large amount ofmaterial can be removed in a relatively short period of time. Inaddition, it will be noted that the wheel, in passing under the work,describes-a slight arc over a relatively long radius with the effectthat the welding point of the tooth tip is imperceptibly higher than thepoints of the tooth tip. In other words, the tooth is ground toward thecenter, so to speak, to an almost unmeasurable degree. This grinding,however, is suicient to prevent featheredged sharpness at the outercorners of the saw tip and, therefore, said tips ground on the presentmachine A will be longer wearing and much more durable. It will beunderstood in this connection that by employing such dimensions for therocking arm 4| it is possible to accumulate the rocking eect of thetooth tip.

After the rst tooth has been ground across the top the feeding movementimparted to the grinding wheel by rotation of the hand wheel 63 isstopped and the foot pedal |35 depressed lowering the saw plate S out ofgrinding position. The saw plate S is then manually rotated bringing thenext tooth up into position for grinding. In so doing such next tooth ismanually rotated at a distance past its desired position and thenpositioned with the indexing lnger H9. It will be noted by reference toFigure 14 that the indexing iinger H9 is free to swing backwardly as thetooth passes it with a sort of latch-like action as the saw plate S ismanually rotated to bring the last tooth into operative position.

Thereupon the foot pedal 35 is released allowing the saw to spring backinto actual position and the hand wheel til reversingly turned,traversing the grinding wheel backwardly across the new tooth tip toremove from it the desired amount of material. The grinding of the sawplate S is thus materially speeded up since the grinding wheel SS'may beset in either direction 9 across the .work and will grind the firsttooth and every odd numbered tooth thereafter on its forward stroke andsimilarly will grind the second tooth and every even numbered tooththereafter upon its return feeding movement. It will, of course, beremembered that all during each feeding stroke the grinding wheel 35 isbeing reciprocated or worked rapidly to-and-fro across the work by therocking movement imparted to it by the motor 6 I Where it isY desired togrind a beveled top face upon the tooth the slide 8l and all theassociated supporting structure may be angularly worked forward orbackward about the center line of the tubular shaft 86 as an axis ofrotation and the grinding operation carried out as above described. Ifit is desired to grind a bevel in one direction on the first and everyodd numbered tooth thereafter and similarly to grind a specificallydirected bevel on the second and every even numbered tooth thereafterthe saw plate will be set up to one angle of inclination and the oddnumbered teeth shifted in the first grinding circuit around the sawplate S. Next the plate will be tilted so that it is set up at theappropriate angle for grinding the desired bevel on the even numberedteeth and every even numbered tooth is ground on the second grindingcircuit of the saw plate S.

It should be noted in this connection that the center line of the shaftl2 and the center line of the tubular shaft 86 are arranged for preciseintersection at right angles to each other at a point out in front ofthe machine beneath the grinding wheel and the grinding wheel should beof such diameter that its point of contact with the work will also beprecisely tangent to the point of intersection between the center linesof the shaftv l2 and shaft, 86. This point of intersection and tangencyis the precise point at which the center point along the top cuttingedge of the tooth tip must be made to coincide. As a practical matter itmay not be economically feasible or proper to dress the grinding wheelvso accurately as to maintain the above mentioned precise v degree oftangency. It, of course, will be obvious that this precision of tangencycan be obtained by incorporating any conventional type of adjustmentmeans into the shaft l2 so that the horizontal axis of the shaft l2 maybe adjusted upwardly or downwardly slightly within appropriate limits tocompensate for wear on the diameter of the wheel. Such adjustment can beachieved by the use of an eccentric shaft, shimmy, or any otherconventional expedient.

It should also be noted in this connection that the saw tip can beground to any desired angle of back-clearance within reasonable limitsby appropriate adjustment of the shaft 21 which swings the entire platei3 upwardly or downwardly around the center line of the shaft l2 so thatthe angular line along which the grinding wheel 39 is fed will not behorizontal, but will be depressed from the horizontal by some selectedangle which is the equivalent of the desired angle of back-clearance.Even in this position, however, the line along which the grinding wheelis fed will intersect the above described point of intersection betweenthe center lines of the shafts I2 and 86 so that the arc of contactbetween the periphery of the grinding wheel and tooth tip willbeprecisely tangent to the point of intersection.

It should be understood that changes and modifications in the form,construction, arrangement, and combinations of the several parts ofsa-ws and similar toothed circular cutters, said.

the saw grinder may be made and substituted for those herein shown anddescribed without departing from the nature and principle of myinvention.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

l. A grinding machine for sharpening circular saws and similar toothedcircular cutters, said grinding machine comprising a base, a first shaftmounted on the base, a plate rockably mounted on and extending radiallyoutwardly from the first shaft, a second shaft mounted on the plateperpendicularly to the rst shaft, a frame rockably mounted on the secondshaft for swinging movement about an axis which lies in a plane disposedat to the axis of the first shaft,

power driven means operatively mounted on the base and operativelyconnected to the frame for continuously rocking the frame to-and-froabout the second shaft, grindingrmeans carried by the frame, means foradjusting the grinding means ltoward and away from the first shaft alonga line parallel to the second shaft, and means on the base forsup-porting the work to be ground, said means being located radiallyoutwardly from the rst shaft and in spaced relation to the path alongwhich the grinding means move due t rocking movement of theV frame.

2. A grinding machine for sharpening circular saws and similar toothedcircularl cutters, said grinding machine comprising a base, a firstshaft mounted on the base, a plate swingably mounted on and extendingradially outwardly from the first shaft for arcuate movement withinpredetermined limits with respect to the axis of the first shaft, meansfor adjustingthe plate to any arcuate position between saidpredetermined limits, means for holding said plate at such position ofadjustment, a frame rockably mounted on and carried by the plate, `saidframe being journaled on the plate for movement about an axis which isperpendicular to a plane passing through the axis of the rst shaft andis spaced radially from said first shaft, grinding means mounted on theframe for adjustable movement toward and away from the first shaft, andmeans on the base for supporting the work to be ground, said means beinglocated radially outwardly from the first shaft and in spaced relationto the vgrinding means. Y

`a rocking frame swingably mounted on the plate for movement about anaxis perpendicular to the shaft and also being shiftable toward and awayfrom the shaft along said axis, grinding means mounted on the frame,means for feeding the plate toward and away from the shaft along saidpath, and an arbor on the base for supporting the work to be ground,said arbor being located in radially spaced parallel relation to theshaft and in spaced relation to the path along A which the plate is fed.

4. A grinding machine for sharpening circular grinding machinecomprising a base, a pivotforming element mounted on the base, a platerockably mounted on and extending radially out- I wardly from thepivot-forming element, a frame rockably mounted on and carried by theplate, said frame being journaled on the plate for movement about anaxis which is perpendicular to a plane passing through the axis of thefirst shaft and is spaced radially from said rst shaft, a grinding wheelmounted on the outer end of the frame for rotation about an axisparallel to the pivot-forming element and for swinging movement aroundthe pivot-forming element in a plane perpendicular to its axis along aradial line, an arbor on the base for supporting the work to be ground,said arbor having its longitudinal axis disposed perpendicularly to andlocated radially outwardly from the pivot-forming element and in theplane along which the grinding wheel swings, and means for adjusting thework supporting means toward and away from the pivotforming element.

5. A grinding machine for sharpening circular saws and similar toothedcircular cutters, said grinding machine comprising a base, apivotforming element mounted on the base, a plate rockably mounted onand extending radially outwardly from the pivot-forming element, a framerockably mounted on and carried by the plate, said frame being journaledon the plate for movement about an axis which is perpendicular to aplane passing through the axis of the first shaft and is spaced radiallyfrom said first shaft, a grinding wheel mounted on the outer end of theframe for rotation about an axis parallel to the pivot-forming elementand for swinging movement around the pivot-forming element in a planeperpendicular to its axis along a radial line, an arbor on the base forsupporting the work to be ground, said arbor having its longitudinalaxis disposed perpendicularly to and located radially outwardly from thepivot-forming element and in the plane along which the grinding wheelswings, and means for rocking the work supporting means about a pivotsubstantially in the same plane with and at right angles to thepivot-forming element.

6. A grinding machine for sharpening circular saws and similar toothedcircular cutters, said grinding machine comprising a base having a flatface forming a plane of reference, a main pivotforming shaft mounted inand extending outwardly from the base with its axis perpendicular to theplane of reference, an elongated plate journaled at one end upon themain pivot-forming shaft and extending radially outwardly therefrom inspaced parallel relation to the plane of reference, a slide-shaftmounted upon and carried by said plate, said slide-shaft being spacedfrom the main pivot-forming shaft with its longitudinal axis positionedin non-radial relation thereto and parallel to the plane of reference, aframe being rockably and slidably journaled upon said shaft andextending radially outwardly therefrom, means carried by the plate andoperatively connected with the frame for adjusting said framelongitudinally to and fro along the slideshaft, power driven means forproducing oscillatory movement, adjustable length means operativelyconnected at its opposite ends of universal joints to the frame and tothe power driven means for transmitting the oscillatory movement of thepower driven means to the frame, whereby to cause said frame to swing toand fro about the axis of the slide-shaft, a grinder shaft journaledupon the frame in radially spaced parallel relation to the slide-shaft,a prime mover also carried by the frame and operatively connected to thegrinder shaft, a grinding wheel mounted concentrically on the grindershaft with its peripheral edge proximate to the longitudinal axis of themain pivot-forming element in such a manner that upon rocking movementof the frame the grinding wheel will oscillate to and fro in an arealocated axially outwardly from one end of the main pivot-forming shaftand by proper sliding adjustment of the frame with respect to theslide-shaft, will be tangent at one point in its arc of swing to theaxis of the main pivot-forming shaft, and work holding means operativelymounted on the base for supporting circular saws and similar toothedcircular cutters in such a manner that a single tooth may be presentedto the grinding wheel in the region of its oscillation.

7. A grinding machine for sharpening circular saws and similar toothedcircular cutters, said grinding machine comprising a base having a fiatface forming a plane of reference, a main pivotforming shaft mounted inand extending outwardly from the base with its axis perpendicular to theplane of reference, an elongated plate journal-ed at one end upon themain pivotforming shaft and extending radially outwardly therefrom inspaced parallel relation to the plane of reference, a slide-shaftmounted upon and carried by said plate, said slide-shaft being spacedfrom the main pivot-forming shaft with its longitudinal axis positionedin nonradial relation thereto and parallel to the plane of reference, aframe being rockably and slidably journaled upon said shaftY andextending radially outwardly therefrom, means carried by the plate andoperatively connected with the frame for adjusting said framelongitudinally to and fro along the slide-shaft, power driven means forproducing oscillatory movement, adjustable length means operativelyconnected at its opposite ends of universal joints to the frame and tothe power driven means for transmitting the oscillatory movement of thepower driven means to the frame, whereby to cause said frame to swing toand fro about the axis of the slideshaft, a grinder shaft journaled uponthe frame in radially spaced parallel relation to the slideshaft, aprime mover also carried by the frame and operatively connected to thegrinder shaft, a grinding wheel mounted concentrically on the grindershaft with its peripheral edge proximate to the longitudinal axis of themain pivot-forming element in such a manner that upon rocking movementof the frame, the grinding wheel will oscillate to and fro in an arealocated axially outwardly from one end of the main pivot-forming shaftand by proper sliding adjustment of the frame with respect to theslide-shaft, will be tangent at one point in its arc of swing to theaxis of the main pivot-forming shaft, and work holding means operativelymounted on the base for supporting circular saws and similar toothedcircular cutters in such a manner that a single tooth may be presentedto the grinding wheel in the region of its oscillation, and meansoperatively associated with the work holding means for feeding the workholding means toward the main pivot-forming shaft.

8. A grinding machine for sharpening circular saws and similar toothedcircular cutters, said grinding machine comprising a base having a flatface forming a plane of reference, a main pivotforming shaft mounted inand extending outwardly from the base with its axis perpendicular 13 tothe plane of reference, an elongated plate journaled at one end upon themain pivot-forming shaft and extending radially outwardly therefrom inspaced parallel relation to the plane of reference, a slide-shaftmounted upon and carried by said plate, said slide-shaft being spacedfrom the main pivot-forming shaft with its longitudinal axis positionedin nonradal relation thereto and parallel to the plane of reference, aframe being rockably and slidably journaled upon said shaft andextending radially outwardly therefrom, means carried by the plate andoperatively connected with the frame for adjusting said framelongitudinally to and fro along the slide-shaft, power driven means forproducing oscillatory movement, adjustable length means operativelyconnected at its opposite ends of universal joints to the frame and tothe power driven means for transmitting the oscillatory movement of thepower driven means to the frame whereby to cause said frame to swing toand fro about the axis of the slide-shaft, a grinder shaft journaledupon the frame in radially spaced parallel relation to the slide-shaft,a prime mover also carried by the frame and operatively connected to thegrinder shaft, a grinding wheel mounted concentrically on the grindershaft with its peripheral edge proximate to the longitudinal axis of themain pivot-forming element in such a manner that upon rocking movementof the frame, the grinding wheel will oscillate to and fro in an arealocated axially outwardly from one end of the main pivot-forming shaftand by proper sliding adjustment of the frame with respect to the,

slide-shaft, will be tangent at one point in its arc of swing to theaxis of the main pivot-forming shaft, work holding means operativelymounted on the base for supporting circular saws and similar toothedcircular cutters in such a manner that a single tooth may be presentedto the grinding wheel in the region of its oscillation, meansoperatively associated with the work holding means for feeding the workholding means toward the main pivot-forming shaft, and indexing meanshaving an abutment face adapted for engagement with each tooth of thesaw or cutter being ground, said abutment face being located in a commonplane with the longitudinal axis of the main pivot-forming shaft so thatthe cutting face of each tooth being ground will be located, duringgrinding operation, in a precisely predetermined relation to the axis ofthe' main pivot-forming shaft.

9. A grinding machine for sharpening circular saws and similar toothedcircular cutters, said grinding machine comprising a base having a flatface forming a plane of reference, a main pivot-forming shaft mounted inand extending outwardly from the base with its axis perpendicular to theplane of reference, an elongated plate journaled at one end upon themain pivotforming shaft and extending radially outwardly therefrom inspaced parallel relation to the plane of reference, a slide-shaftmounted upon and carried by said plate, said slide-shaft being spacedfrom the main pivot-forming shaft with 14 its longitudinal axispositioned in non-radial relation thereto and parallel to the plane ofreference, a frame being rockably and slidably journaled upon said shaftand extending radially outwardly therefrom, means carried by the plateand operatively connected with the frame for adjusting said framelongitudinally to and fro along the slide-shaft, power driven means forproducing oscillatory movement, adjustable length means operativelyconnected at its opposite ends of universal joints to the frame and tothe power driven means for transmitting the oscillatory movement of thepower driven means to the frame whereby to cause said frame to swing toand fro about the axis of the slide-shaft, a grinder shaft journaledupon the frame in radially spaced parallel relation to the slide-shaft,a prime mover also carried by the frame and operatively connected to thegrinder shaft, a grinding wheel mounted concentrically on the grindershaft with its peripheral edge proximate to the longitudinal axis of themain pivot-forming element in such a manner that upon rocking movementof the frame, the grinding wheel will oscillate to and fro in an arealocated axially outwardly from one end of the main pivot-forming shaftand by proper sliding adjustment of the fr ame with respect to theslide-shaft, will be tangent at one point in its arc of swing to theaxis of the main pivot-forming shaft, work holding means operativelymounted on the base for supporting circular saws and similar toothedcircular cutters in such a manner that a single tooth may be presentedto the grinding wheel in the region of its oscillation, meansoperatively associated with the work holding means for feeding the workholding means toward the main pivot-forming shaft, and indexing meanshaving an abutment face adapted for engagement with each tooth of thesaw or cutter being ground, said abutment face being located in a commonplane with the longitudinal axis of the main pivot-forming shaft so thatthe cutting face of each tooth being ground will be located, duringgrinding operation, in a precisely predetermined relation to the axis ofthe main pivot-forming shaft, said indexing means being swingable towardand away from the Work so as to be disengaged from each tooth after thegrinding operation on each tooth has been completed so that a successivetooth can be moved upon into grinding position. Y

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 580,875 Littlejohns Apr. 20, 1897 1,453,765 Octave May 1, 19232,202,587 Kitchen May 28, 1940 2,217,145 Stihl Oct. 8, 1940 2,278,314Houchin Mar. 31, 1942 2,410,274 Drake Oct. 29, 1946 2,425,234 Erwin etalAug. 5, 1947 2,547,553 Battocch Apr. 3, 1951

